JPS5769913A - Input buffer circuit for measuring device - Google Patents
Input buffer circuit for measuring deviceInfo
- Publication number
- JPS5769913A JPS5769913A JP55146482A JP14648280A JPS5769913A JP S5769913 A JPS5769913 A JP S5769913A JP 55146482 A JP55146482 A JP 55146482A JP 14648280 A JP14648280 A JP 14648280A JP S5769913 A JPS5769913 A JP S5769913A
- Authority
- JP
- Japan
- Prior art keywords
- input
- power supply
- fet16
- lowering
- buffer amplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
PURPOSE: To prevent the lowering in impedance due to power supply interruption surely, by providing a photocoupling element at the input of a buffer amplifier, inserting a photodetector in series with it, connecting the light emitting element to the power supply and avoiding the limit of input range.
CONSTITUTION: A photodetector FET16 of a photocoupling element 14 is inserted between the + input terminal of an input buffer amplifier 11 and an input terminal 15 of a buffer circuit, and a power supply voltage Vcc is given to a light emitting element 17 via a resistor 18. The FET16 is at a low resistance through the light emission of the element 17 during the application of power supply voltage, and when the power supply is interrupted, the FET16 is at high resistance to compensate the lowering in the input impedance of the buffer amplifier. With this constitution, the input voltage range of a measuring unit, especially a limit is unnecessary, and the lowering in the input impedance of the measuring unit can be prevented at the interruption of power supply surely.
COPYRIGHT: (C)1982,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP55146482A JPS5769913A (en) | 1980-10-20 | 1980-10-20 | Input buffer circuit for measuring device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP55146482A JPS5769913A (en) | 1980-10-20 | 1980-10-20 | Input buffer circuit for measuring device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5769913A true JPS5769913A (en) | 1982-04-30 |
JPS641972B2 JPS641972B2 (en) | 1989-01-13 |
Family
ID=15408631
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP55146482A Granted JPS5769913A (en) | 1980-10-20 | 1980-10-20 | Input buffer circuit for measuring device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5769913A (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54107250A (en) * | 1978-02-10 | 1979-08-22 | Hitachi Ltd | Signal transfer circuit using photo coupler |
JPS5564158A (en) * | 1978-11-01 | 1980-05-14 | Nippon Denso Co Ltd | Ignition distributor |
JPS5587717A (en) * | 1978-12-05 | 1980-07-02 | Haessle Ab | Cardiotonic glycoside containing medicine |
-
1980
- 1980-10-20 JP JP55146482A patent/JPS5769913A/en active Granted
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54107250A (en) * | 1978-02-10 | 1979-08-22 | Hitachi Ltd | Signal transfer circuit using photo coupler |
JPS5564158A (en) * | 1978-11-01 | 1980-05-14 | Nippon Denso Co Ltd | Ignition distributor |
JPS5587717A (en) * | 1978-12-05 | 1980-07-02 | Haessle Ab | Cardiotonic glycoside containing medicine |
Also Published As
Publication number | Publication date |
---|---|
JPS641972B2 (en) | 1989-01-13 |
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